Common Butterfly Valve Failures And Repair Solutions

Butterfly valves are widely used in fluid control systems, but prolonged operation in harsh environments can lead to varying degrees of wear and failure. This article summarizes some common problems that may occur with butterfly valves and provides solutions to address them.

Seal Leakage

Causes of Failure：

1. Aging, wear, or corrosion of the sealing ring due to the medium.

2. Poor fit between the valve seat and the disc.

3. Improper installation, leading to uneven sealing surfaces.

How to repair：

1. Replace the sealing material. Choose appropriate sealing materials based on the nature of the medium and operating temperature, such as EPDM or PTFE.

2. Adjust the clearance between the valve seat and the disc to ensure a tight fit. If the gap is too large, it can be resolved by replacing the sealing gasket or adjusting the bolt tightening force.

3. Re-align the flanges and tighten the bolts evenly using a torque wrench. Avoid excessive force or applying too much external pressure when the valve is in the closed position. During operation, follow the proper procedures to open and close the valve slowly to prevent impact and vibration.

Incomplete Valve Closure and Opening

Causes of Failure：

1. Loose or damaged connection between the stem and the disc.

2. Bent or deformed valve stem.

3. Excessive medium pressure exceeding the valve’s rated capacity.

4. Foreign objects stuck inside the valve.

How to repair：

1. Inspect the connection between the valve stem and the disc. If loose or damaged, tighten or replace the components. Ensure a secure and reliable connection to properly transmit torque.

2. Examine the valve stem. If it is bent or deformed, correct or replace it. Use specialized tools to inspect and realign the stem, ensuring its straightness and strength.

3. If the medium pressure is too high, check for abnormalities in the pipeline system, such as blockages or overloading. Pressure reduction measures can be taken, such as installing a pressure relief valve or adjusting the pipeline layout.

4. Open the valve and remove any foreign objects inside. Use appropriate tools to extract debris, or disassemble the valve for thorough cleaning. Before installation, ensure the pipeline is clean to prevent foreign objects from entering the valve.

Excessive Operating Torque

Possible Causes：

1. Excessive friction between the valve stem and packing.

2. High friction between the disc and valve body.

3. Improper installation causing uneven force distribution.

4. Malfunction in the operating mechanism.

How to repair：

1. Adjust the packing gland tightness and apply an appropriate amount of lubricant. If the packing is aged or damaged, replace it promptly to ensure proper friction levels between the stem and packing.

2. Check the clearance between the disc and the valve body. If necessary, adjust or repair it. Methods such as grinding or polishing can help reduce friction and ensure smooth disc movement.

3. Inspect the valve installation to ensure it is properly positioned and securely mounted. Avoid external force or deformation during installation, which could lead to uneven stress distribution.

4. Examine the operating mechanism, including the handle and gearbox, for any faults. If issues are found, repair or replace the faulty components to ensure smooth torque transmission and easy valve operation.

Valve Vibration and Noise

Possible Causes：

1. Excessive flow velocity, causing turbulence and impact.

2. Loose valve installation leading to resonance.

3. Uneven clearance between the disc and valve body.

4. Improper operation, such as opening or closing the valve too quickly.

How to repair：

1. Adjust the pipeline system’s flow rate and pressure to reduce the medium velocity. Installing a throttling device or adjusting the pump’s output can help prevent excessive turbulence and impact.

2. Check the valve installation to ensure it is securely mounted. Adding supports or fixing components can help prevent vibration during operation.

3. Adjust the clearance between the disc and the valve body to ensure uniformity. If the gap is uneven, tightening bolts or replacing the sealing gasket can help resolve the issue.

4. Operate the valve correctly, avoiding sudden opening or closing. The valve should be opened and closed gradually to minimize impact and noise.

Image source: iStock

Preventive Maintenance Recommendations

• Periodic Inspection: Check sealing performance, lubrication status, and bolt tightness every six months.

• Spare Parts Inventory: Keep essential spare parts such as sealing rings, valve stems, and packing on hand to minimize downtime.

• Operator Training: Ensure operators are familiar with valve characteristics, including maximum pressure differential and temperature limits.

When using butterfly valves, any issues should be promptly analyzed, and appropriate corrective actions should be taken. Regular maintenance and servicing can effectively extend the valve’s lifespan and ensure reliable operation.

Thank you for reading this article. If you have any further questions, please feel free to contact TFW Valve. As a professional butterfly valve manufacturer, TFW Valve is committed to providing customers with efficient and reliable solutions. If you encounter challenges in valve selection, fault diagnosis, or system optimization, our expert team is ready to assist you with technical support.